Superformance Questions

[cycleguy55]

Originally Posted by sunman

I suggest you look closer at the cap rubber seal
It looks like it is compressed at contact area and maybe cracked
Maybe it’s just the photo but
Put On A New Cap First

Agreed. When I zoom in on that image it appears the lower seal is in rough shape and unlikely to properly seal against the expansion tank.

The bigger problem and the likely culprit of the coolant leak, however, is the upper seal. Look closely at the bottom part of it in the photo - it looks like it's torn and may have even folded over a bit when previously installed. That won't seal and will allow expanding coolant to leak. If that seal isn't leaking all the extra coolant should flow out the hose, not past the seal and over the expansion tank.